2004 to 2020 Mazda 3 Forum and Mazdaspeed 3 Forums banner

Low-temp light

Tags
light lowtemp
12K views 12 replies 11 participants last post by  stephane 
#1 ·
Does everyone else's low-temp light stay on for a really long time? On our Outback, the low-temp light always goes out within a mile or two of driving, but I've been noticing that the light in my '15 S-GT stays on for several miles. Today it never did go out in maybe 5-6 miles of driving; it was -2F outside, but the heater was actually blowing warm air and the light was still on.

Anyone else care to comment on this?
 
#2 ·
15 sGT sedan here. Mine seems to work how it's supposed to, always goes out when the car is warm. I rarely to never just start and drive, espescially if it's cold out, so I couldn't comment on how much distance I travel until it goes out.

I'm in BC Canada so see some cold temps in the winter.
 
#5 ·
I recall reading elsewhere on this forum that the blue low temp light is supposed to go out when coolant temp rises above 120F*. Given the -2F* ambient temps, driving 5~6 miles with the light still on seems normal to me. Especially if you just drive off without letting it sit a long time warming up. My 3S GT is garaged, and I'll just start it up and go within 30 seconds or so, and when it's that cold outside it will take several miles before the blue light goes out. I keep revs under 3K, and drive gently until it's up to operating temp; flogging it will make it warm up quicker, but is not a smart thing to do.

As for the heater, you'll feel warm air out of the heater because it's blowing air over a heater core that is a lot warmer than the -2 ambient temps that were previously hitting your skin.
 
#6 ·
5-6 miles at what speed? It was about -2 F here this morning too, but the temp doesn't seem to affect the time it takes to go off too much, takes about 3 miles and maybe took half a mile longer today if that. My drives go right to 40-45 mph if that's a difference. Also I have the 2.0 engine not the 2.5, so that could account for some difference. And I start out from a garage that's at least 30 degrees warmer than outside, maybe more. And it may make a tiny bit of difference that I typically don't have the climate fan running until after it goes out.
 
#7 ·
Yeah, I forgot that one big difference was that the car is always parked overnight in our garage, which rarely gets colder than the 20s. But the time that it was taking a really long time it had been sitting outside in sub-zero temps while I was at the gym. Also, the automatic trans short-shifts for economy and the revs barely go above 1500 or so in around-town driving.

The CVT in the Outback actually keeps the revs a good bit higher and is probably one reason why that seems to heat up faster (also no reason whey they'd be using the same algorithm either).
 
#8 ·
It takes about 3 miles/5 minutes on very cold mornings (very cold for this area being 5-20 degrees F) during my typical morning commute for the car to warm up enough to turn the blue light off. As others noted if you're driving very gently at low speeds it'll take longer. I never flog it when the blue light is on (no one should) but I notice highway speeds at sustained higher revs will definitely hasten the warm up versus just staying on local roads. I live only a mile from the main highway so that helps.

One other thing that might be slowing your process is if you run the front defroster too soon. The automatic climate control is designed to not run until the engine warms up a bit. However, you can override that if you hit the windscreen defrost button as the system assumes your need to possibly defog the interior glass might outweigh the need for hot air to defrost the outside (especially if you deice the glass with a scraper as many do) or warm the cabin. In that situation it'll take longer to warm the coolant because what little warmth there is coming off is being siphoned off for the front window.
 
#9 ·
The temp light goes out at 130 degrees, at least, that's what my scangauge reads. If you have the heater on, the heat from the engine will dissipate faster. The coolant will run through the heater core, exchange heat at a greater rate. The end result is that it will take more time to come up to operating temps. That is all the more reason to get heated seats, they're great!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top